In a system for performing an action regarding an account in response to an electronic communication received from a sender by a receiver, wherein the electronic communication includes sender identity information associated with the account and predetermined encoded information derived using a private key of a public-private key pair, and wherein the public key of the pair has been associated with the account by the receiver such that the public key is retrievable based on the sender identity information, a method of validating the identity of the sender for the electronic communication includes: (a) retrieving the public key based on the received sender identity information; and (b) comparing a function of the public key and the predetermined encoded information with a function of the electronic message. Neither a PIN nor a password is required to be transmitted to the receiver for validating the identity of the sender.